Patent GB-773887-A (GB)
Title: Anion exchange resins of enhanced operating capacity
IPC: C08F8/32
Filed: 1954-04-12
Abstract: An anion-exchange resin is prepared by halogenating a copolymer of a major molar proportion of one or more monovinyl aryl compounds and one or more polyvinyl aryl or di-unsaturated aliphatic cross-linking compounds until the halogen content does not exceed 4 per cent, preferably 0.2 to 4 per cent based on the weight of the unhalogenated copolymer, haloalkylating and then aminating the resulting haloalkylated halogenated copolymer. Monovinyl aryl compounds specified are styrene, o-, m- and p-methyl and ethyl styrenes, vinyl naphthalenes, vinyl anthracene and o-, m- and p-chloro- and bromostyrenes.  The cross-linking compounds used in an amount of 0.1 to 40 per cent of the mixture may be divinyl benzene, toluene, naphthalene, ethyl benzene or xylene, or divinyl sulphone or ketone, vinyl or divinyl acetylene, vinyl maleate, acrylate, methacrylate, or ethacrylate, divinyl oxalate, maleate, malonate or succinate ethylene or diethylene glycol dimethacrylate or diacrylate, glycerine dimethacrylate, or the corresponding allyl or 3-n-butenyl derivatives.  Catalysts such as ozone, oxygen, hydrogen, acetyl and benzoyl peroxides, t-butyl hydroperoxide, persulphates, azobisisobutyronitrile and azobiscyclopropiopropylnitrile and suspending agents such as gelatine, carboxymethylcellulose, methyl cellulose or casein and boric acid or alkali are used in the polymerization and the halogenating agents may be elemental chlorine or bromine, used with iodine or ultra-violet light, or sulphuryl chloride, monochloride and phosphorus pentabromide with or without peroxide catalysts.  In a modification the halogen may be present in one of the monomers.  Haloalkylation may be effected by reacting with a haloether or a mixture of an alkyl halide and a halogen acid using a catalyst such as aluminium, zinc and stannic chlorides; by reacting with an aldehyde and halogen acid, e.g. paraformaldehyde and hydrochloric acid, or a dihaloalkane and a Friedel-Crafts catalyst, e.g. ethylene dichloride and aluminium chloride; or if alkyl substituted monovinyl aryl compounds are present by direct halogenation, firstly with and then without a carrier such as iodine, ferric and aluminium chlorides.  Suitable aminating agents are ammonia, propylamine, ethylenediamine, dimethyl, diethyl, dipropyl and di-n-butyl amines, methyl and ethyl ethanolamines and diethanolamine, dibenzylamine, methylaniline, diethylenetriamine, triethylene tetramine, tetraethylenepentamine, piperazine, piperidine and morpholine, trimethyl, triethyl, and tripropylamines, benzyldimethylamine, dimethylethanolamine and methyldiethanolamine, or alternatively the p-, s-, and t-amines may be quaternized with agents such as methyl and ethyl chlorides, bromides and iodides, dimethyl, diethyl, dipropyl and dibutyl sulphates, epichlorohydrin and methyl toluene or benzene sulphonates.  In examples, copolymers of (1) styrene, divinyl benzene and ethyl vinyl benzene; (2) styrene, o-chlorostyrene and divinyl and ethyl vinyl benzenes; (3) styrene, o-chlorostyrene and ethylene glycol dimethacrylate; (4) and (5) styrene and ethylene glycol dimethacrylate are prepared in aqueous medium using benzoyl peroxide as catalyst to give beads which are halogenated where necessary with a sulphuryl chloride, haloalkylated with elemental halogen in the presence of a Friedel-Crafts catalyst and aminated using trimethylamine, dimethanolamine, and tetraethylenepentamine.  For use as anion exchange resins the ammonium salts are converted to hydroxides by treatment with dilute alkali and may be regenerated in a similar way.